A solid oxide fuel cell is an electrochemical cell that burns a fuel to generate heat and electricity. In one embodiment, the fuel cell consists of a multilayered tube that is electrically connected to other tubes. The electrical connection between the cells is made through a ceramic interconnection (or a fuel electrode material covering the interconnection) on one cell and the fuel electrode, which can be metallic or mixed metallic-ceramic, on an adjacent cell. In between the interconnection of one cell (or the fuel electrode material covering the interconnection of one cell) and the fuel electrode of another cell is placed a spongy nickel felt. The nickel felt permits electrical contact between the two cells to be maintained during cell expansion and contraction which occurs as the cells are heated and cooled. It has been found, however, that the electrical connection between the spongy nickel felt and the interconnection is sometimes poor, which increases the resistance of the cell connections and reduces the efficiency of connected cells. If fuel electrode material covers the interconnection, the poor electrical connection is between the interconnection and the fuel electrode material.
Attempts were made to solve this problem by applying a deposit of nickel on top of the interconnection. However, forming the nickel deposit by conventional techniques, such as sputtering or plasma spraying, are not acceptable processes because they are uneconomical or introduce stresses into the cell structure.